Boost in nerve-growth protein helps explain why running supports brain health

Exercise increases levels of a chemical involved in brain cell growth, which bolsters the release of the "feel good" hormone dopamine, a new study shows. Dopamine is known to play a key role in movement, motivation, and learning.

Experts have long understood that regular running raises dopamine activity in the brain and may protect nerve cells from damage. In addition, past research has tied exercise-driven boosts in the dopamine-triggering chemical called brain-derived neurotrophic factor (BDNF) and in dopamine levels to improvements in learning and memory. However, the precise way these three factors interact has until now remained unclear.

Led by researchers at NYU Grossman School of Medicine, the investigation showed that mice running on a wheel for 30 days had a 40% increase in dopamine release in the dorsal stratium, the part of the brain involved in movement, compared to levels in mice that did not exercise. The runners also showed a nearly 60% increase in BDNF levels compared to their non-running counterparts. Notably, the increase in dopamine release remained elevated even after a week of rest. Additionally, when BDNF levels were artificially reduced, running did not lead to additional dopamine release.

"Our findings suggest that BDNF plays a key role in the long-lasting changes that occur in the brain as a result of running," says study lead author and neurobiologist Guendalina Bastioli, PhD. "Not only do these results help explain why exercise makes you move, think, and feel better, they also show that these benefits continue even if you do not work out every day," adds Bastioli, a postdoctoral fellow in the Department of Neuroscience at NYU Langone Health.

While researchers have previously measured dopamine activity during running, the new investigation provides insight into the longer-term behavior of the hormone and its effects on the brain well after exercise stops, according to Bastioli. The report is publishing online May 16 in the Journal of Neuroscience.

For the investigation, researchers provided dozens of male mice with unlimited access to either a freely rotating wheel or a locked wheel that could not move. After one month, the team measured dopamine release and BDNF levels in brain slices. They repeated this same process on a new group of rodents, some of which had been genetically modified to produce half as much BDNF as regular mice.

The study authors note that patients with Parkinson's disease and other movement disorders are often treated with drugs that mimic dopamine's effects on motor neurons. However, the mechanism behind dopamine's role in this protective benefit of exercise had not been thoroughly explored.

"Our results help us understand why exercise alleviates the symptoms of Parkinson's disease, as well as those of neuropsychiatric disorders such as depression," says study senior author and neuroscientist Margaret Rice, PhD. "Now that we know why physical activity helps, we can explore it as a means of augmenting or even replacing the use of dopamine-enhancing drugs in these patients."

Rice, a professor in the Departments of Neurosurgery and Neuroscience and Physiology at NYU Langone, cautions that while the preliminary findings in rodents were promising, future studies in humans will be required to fully understand the role of BDNF and dopamine in Parkinson's disease.

She adds that the study team next plans to investigate the relationship between exercise and these chemicals in female mice, which notably run more frequently than males. In addition, the researchers intend to directly examine whether active mice indeed have improved motor skills compared with those with limited physical activity.

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From couch to ultra-marathon – mental imagery technique can aid running challenge completion

A motivational intervention known as functional imagery training (FIT) can help self-professed non-runners to complete an ultra-marathon (50km plus), according to new research.

The study, led by the University of Plymouth, started by examining the motivation of 31 non-runners who wanted to get fitter, by giving them a recognised behaviour change technique, often used by counsellors, known as Motivational Interviewing (MI). Participants were then left for five months to do whatever they presumed would benefit their fitness and health. After this period all were contacted and asked if they would consider completing an ultra-marathon.

Fifteen participants went on to express an interest in attempting an ultra-marathon as they continued to improve their fitness. Seven were randomly assigned FIT, while eight continued with just MI.

MI is a technique that sees a counsellor support someone to develop, highlight and verbalise their need or motivation for change, and their reasons for wanting to change. Functional Imagery Training builds on MI, as it teaches clients how to elicit and practice motivational imagery themselves, with participants encouraged to utilise all their senses to visualise how it would feel to achieve their goal.

Of the eight participants in the MI only group, four started the race, and two finished. Meanwhile, all seven of the FIT group started, and six finished -- showing that those assigned to the technique were five times more likely to complete the challenge.

While researchers acknowledge the small population size, the study, published in the Journal of Imagery Research in Sport and Physical Activity, adds to the growing body of evidence that FIT can significantly reinforce a person's motivation to complete a challenging goal.

FIT has also previously been shown to boost weight loss, with another Plymouth-led study showing that overweight people who used it lost an average of five times more weight than those using motivational interviewing alone.

Developed at the University of Plymouth, FIT is a unique approach to behaviour change that uses mental imagery to motivate change.

It teaches people new ways of thinking about their immediate future to help them stay motivated as they achieve each small step towards their goal -- with users describing it as a 'mindset shift', where they exercised because they wanted to, rather than feeling they had to.

For example, at difficult points in the race, a participant in the new study -- a teacher -- pictured the conversation they would have at work on Monday morning: visualising the staff room, holding a coffee in hand, imagining the smell and the taste, talking about the challenges with a peer, then using this self-developed image to imagine the feeling at the finish line, as they go from little exercise to ultra-athlete.

Lead author Dr Jon Rhodes, who has worked with professional athletes to improve their resilience, said: "An ultra-marathon requires a huge amount of mental, as well as physical, strength -- even from people who run regularly. Trialling Functional Imagery Training on historically self-professed non-runners was a real test of its efficacy, and to see that it made a difference was a promising finding.

"It shows that multi-sensory imagery is the key difference between those who reach the starting line and then go on to finish, and those who do not -- showing it is critical to maintaining changes and pushing the boundaries of physical and mental performance."

Melissa King, aged 38 from Newquay in Cornwall, was allocated the FIT intervention as she prepared for the Exmoor Ultra Marathon earlier this year. Completing the event successfully, she said: "My honest reason for starting running in the first place was just to see if I could do it.

"FIT has been a huge mindset shift, and I now use imagery as a way to reset; to ground me and help me to focus on being present, appreciating why I am here while also prompting me to cue my immediate, medium- and long-term goals. Having never run before, my ultimate aim is now a running trip in South America which will take a couple of months. It's in three years' time, so I'm starting training early and really embracing the challenge."

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Major risk of injury for recreational runners

 Almost half of all recreational runners incur injuries, mostly relating to knees, calves or Achilles tendons, and the level of risk is equally high whatever your age, gender or running experience. These are the findings of a thesis within sport science.

Doctoral student Jonatan Jungmalm recruited a little over 200 recreational runners from the list of entrants for the Göteborgsvarvet Half Marathon and monitored them over a period of one year. To take part in the study, they had to have been running for at least a year, have run an average of at least 15 km per week over the past year and have been injury free for at least six months. The participants were men and women in the age range 18-55.

Calculation shows injury for half of runners

Over the year of the study, the recreational runners filled in a training diary, entering information about how far they ran each day and whether they felt any pain. Those who suffered sudden injury or felt pain for a prolonged period were examined by a sports doctor.

"A third of the participants were injured over the course of the study. But if you also take account of the participants who dropped out of the study, it is reasonable to assume that almost half of all recreational runners injure themselves in a year," states Jonatan Jungmalm.

Jonatan used a particular statistical method to calculate the proportion of injured runners, taking into account the rate of dropout that is common in studies based on voluntary participation.

Injuries to knee, calf and Achilles tendon

Of those hit by injury, half had problems with their knees, calves or Achilles tendons.

"Few of the injuries were long-lasting. But all the injuries prevented the runners from exercising as usual," says Jonatan.

No difference was found in terms of gender, age, running experience or weight between those who injured themselves and those who did not.

"However, those who had previously been injured were more likely to be affected again."

Multiple physical tests

All the participants were put through a series of physical tests before the study, ranging from strength tests and mobility tests to tests of running style.

"Those who had relatively weak outer thighs faced a higher risk of injury. Those with late pronation in their running gait were also at higher risk. However, having a weak torso or limited muscle flexibility was of no great significance."

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